Wireless communication devices in many forms are becoming increasingly popular. The term "wireless communication device" in this context encompasses cellular telephones, patio telephones, cordless telephones in their many different forms, personal communication devices, and the like.
Wireless communication devices are characterized by being easily transportable by the user.
Typically, wireless communication devices include an antenna arrangement for providing the wireless communication. The antenna arrangement may provide, in cooperation with circuitry of the wireless communication device, transmit, receive or transceiving functions for the wireless communication device. Desirable antenna arrangements are small, reliable and manufactureable. Since the wireless communication device is indeed transportable, desirable antenna arrangements are also typically moveable between a stowed and an unstowed position, for example, a retracted and an extended position, respectively.
Designers of antenna arrangements strive to optimize the size, reliability and manufacturability of the antenna arrangement while achieving desirable performance for the antenna arrangement. Since technology is driving the size of wireless communication devices to be smaller, the antenna arrangement for those smaller devices must also be made smaller to preserve the antenna arrangement's stowable feature and desirable performance. FIGS. 1-3 illustrate first, second and third antenna arrangements for a wireless communication device which seek to optimize both size and performance of the antenna arrangement in accordance with the prior art.
FIG. 1 illustrates the first antenna arrangement 102 for a wireless communication device 100 in accordance with the prior art. A detailed description of the antenna arrangement 102 in FIG. 1 is given in U.S. Pat. No. 4,121,218. The antenna arrangement 102 of FIG. 1 generally includes a helical antenna 104 and an extendible half-wave antenna 106. The helical antenna is coupled to circuitry 108 of the wireless communication device 100. The extendible half-wave antenna 106 is adapted to be capacitively coupled to the helical antenna 104 when in the extended position and to be substantially decoupled therefrom when in a retracted position (shown in dotted lines). Advantages of the antenna arrangement 102 include contactless coupling between the helical antenna 104 and the extendible half-wave antenna 106 and the performance of the antenna arrangement as indicated by the height 112 where the current maximum of the extendible half-wave antenna 106 occurs when the extendible half-wave antenna 106 is extended. However, a disadvantage of the antenna arrangement 102 is that its overall physical height 110 is too long to meet present day needs of miniature wireless communication devices.
FIG. 2 illustrates a second antenna arrangement 202 for a communication device 200 in accordance with the prior art. A detailed description of the antenna arrangement 202 in FIG. 2 is given in U.S. Pat. No. 4,868,576. The antenna arrangement 202 includes a helical antenna 204 coupled to circuitry 208 and an extendible half-wave helical antenna 206. An advantage of the antenna arrangement 202 over the antenna arrangement 102 of FIG. 1 is that the height 210 is lower than the height 110 of the antenna arrangement 102. However, a disadvantage of the antenna arrangement 202 is that the height 212 where the current maximum of the extendible half-wave antenna 206 occurs when the extendible half-wave antenna 206 is extended, is lower than the height 112 where the current maximum occurs in FIG. 1. Therefore, the performance of the antenna arrangement 202 was sacrificed for a shorter antenna.
FIG. 3 illustrates the third antenna arrangement 302 for a wireless communication device 300 in accordance with the prior art. The antenna arrangement 302 generally includes a first straight portion 304 and a second helical portion 306 which is electrically isolated from the first straight portion 304. The straight portion and the helical portion 306 each have an electrical wavelength of 1/4 wavelength. The straight portion 304 includes a terminal 310 for connection to a connector 312 when the antenna arrangement is extended. Likewise, the helical portion 306 includes a terminal 314 for connection to the connector 312 when the antenna arrangement is retracted. Circuitry 308 is coupled to the antenna arrangement 302 via a connector 312. An advantage of the antenna arrangement 302 is that its height 316 is reduced even further than that represented in FIGS. 1 or 2. However, a disadvantage of the antenna arrangement 302 is that the height where the current maximum occurs when the antenna arrangement 302 is extended is much lower (shown below the housing of the device) than the height of the current maximum as shown in FIGS. 1 or 2. A further disadvantage is that metallic contacts of the connector produces electrical noise which reduces reliability.
Therefore, there is a need for an antenna arrangement for a wireless communication device having further reduced dimensions while achieving desirable performance as well as maintaining acceptable reliability and manufacturability.